Undersea optical communication systems may include an optical transmission path extending between shore stations separated by distances of 10,000 km or more. The optical transmission path may include an optical fiber cable coupled from one shore station to another through numerous elements, such as repeaters, branching units, etc. The optical fiber cable may include multiple optical fiber pairs for bi-directional transmission of information, e.g. on a plurality of separate wavelength channels in a wavelength division multiplexed (WDM) system, and a power conductor for providing electrical energy required for operation of elements connected thereto. The optical fiber cable, as well as housings associated with elements connected thereto, may rest on the ocean floor.
During the operational life of an undersea optical communication system, the elements thereof may require repair, replacement, modification or upgrade. To perform any of these tasks the cable and the subject element must be located on the ocean floor. To locate the element, a ship may travel to an expected general location of the element, and a search may be conducted to specifically locate the element.
In addition, various elements within an undersea system may be selectively configurable by signaling from a shore station. A branching unit, for example, may be configured to a grounded or ungrounded state using a control signal sent from an associated transceiver. It may be useful to in such a system to obtain a confirmation signal from the element confirming that it has been configured in the desired operating condition.